In a world filled with lobbyists for most companies, it is safe to assume that the business that manufactures the machines that put the decision makers into power would also partake in this practice. They probably would not openly admit it, and maybe it isn't exactly legal, but that has never stopped anyone before from using any advantage to get ahead of the competition. Any company is liable to have an interest in a certain political party in order to get regulations in their favor.
It isn't really a mystery that developers of certain voting machines would have their political opinions lie one way or the other. This would imply that they certainly have the power to swing elections in their party's favor by manipulating the machines that they create. Although they would suggest otherwise, it is important that we keep ties on them.